Source : Webster's Revised Unabridged Dictionary (1913)

Knee \Knee\, n. [OE. kne, cneo, As. cne['o], cne['o]w; akin to
   OS. knio, kneo, OFries. kn[=i], G. & D. knie, OHG. chniu,
   chneo, Icel. kn?, Sw. kn["a],Dan. kn[ae], Goth. kniu, L.
   genu, Gr. ?, Skr. j[=a]nu, ? Cf. {Genuflection}.]
   1. In man, the joint in the middle part of the leg.

   2. (Anat.)
      (a) The joint, or region of the joint, between the thigh
          and leg.
      (b) In the horse and allied animals, the carpal joint,
          corresponding to the wrist in man.

   3. (Mech. & Shipbuilding) A piece of timber or metal formed
      with an angle somewhat in the shape of the human knee when
      bent.

   4. A bending of the knee, as in respect or courtesy.

            Give them title, knee, and approbation. --Shak.

   {Knee breeches}. See under {Breeches}.

   {Knee holly}, {Knee holm} (Bot.), butcher's broom.

   {Knee jerk} (Physiol.) a jerk or kick produced by a blow or
      sudden strain upon the patellar tendon of the knee, which
      causes a sudden contraction of the quadriceps muscle; one
      of the so-called tendon reflexes.

   {Knee joint}. See in the Vocabulary.

   {Knee timber}, timber with knees or angles in it.

   {Knee tribute}, or {Knee worship}, tribute paid by kneeling;
      worship by genuflection. [Obs.] ``Knee tribute yet
      unpaid.'' --Milton.

Breeches \Breech"es\, n. pl. [OE. brech, brek, AS. br[=e]k, pl.
   of br[=o]c breech, breeches; akin to Icel. br[=o]k breeches,
   ODan. brog, D. broek, G. bruch; cf. L. bracae, braccae, which
   is of Celtic origin. Cf. {Brail}.]
   1. A garment worn by men, covering the hips and thighs;
      smallclothes.

            His jacket was red, and his breeches were blue.
                                                  --Coleridge.

   2. Trousers; pantaloons. [Colloq.]

   {Breeches buoy}, in the life-saving service, a pair of canvas
      breeches depending from an annular or beltlike life buoy
      which is usually of cork. This contrivance, inclosing the
      person to be rescued, is hung by short ropes from a block
      which runs upon the hawser stretched from the ship to the
      shore, and is drawn to land by hauling lines.

   {Breeches pipe}, a forked pipe forming two branches united at
      one end.

   {Knee breeches}, breeches coming to the knee, and buckled or
      fastened there; smallclothes.

   {To wear the breeches}, to usurp the authority of the
      husband; -- said of a wife. [Colloq.]

Source : WordNet®

knee breeches
     n : trousers ending above the knee [syn: {breeches}, {knee pants},
          {knickerbockers}, {knickers}]